1. Field of Invention
The present invention relates to an MOCVD apparatus and method in which a source gas, as a mixture of an MO source gas with an oxidizing gas, is supplied to thereby form films.
2. Description of Related Art
Related art MOCVD (metal organic chemical vapor deposition) apparatus are CVD apparatus using an organometallic compound as a source or raw material, and generally use powders or other raw materials which are solid or liquid at normal pressure and temperature. In these MOCVD apparatus, such a raw material is provided in a container, is heated under reduced pressure and is thereby vaporized. The vaporized gaseous material is transmitted with a carrier gas toward a deposition chamber. A passage through which the source gas flows is thereby always heated. In addition, oxygen gas is supplied to the passage of the source gas. Then, a gaseous mixture of the source gas and oxygen gas is supplied into the deposition chamber. The material used in MOCVD remains gaseous before reaching the substrate in the deposition chamber, is thermally decomposed and undergoes a combustion reaction on the substrate to thereby form a thin film on the substrate.
In the related art MOCVD apparatus, the deposition chamber has a large volume or capacity, the source gas supplied to the deposition chamber adiabatically expands and thereby the temperature thereof decreases. Such a source gas having a decreased temperature may not form a thin film having satisfactory properties on the substrate.
In addition, the oxygen gas, to mix with the source gas, is supplied at room temperature, and thereby temperature of the source gas further decreases. Thus, a thin film having satisfactory quality cannot be significantly obtained.